docs: def new_graph(self, name, data=None, **attr):
          """Return a new instance of type Graph, initialized with the given
          data if provided.
  
          :arg name: a name for the graph
          :arg data: dictionary or NetworkX graph object providing initial state
  
          """
          self._init_graph(name, 'Graph')
          g = Graph(self, name, data, **attr)
          self._graph_objs[name] = g
          return g